Boats try to help the sinking Sewol ferry off South Korea‚??s southern coast on April 16, 2014. / South Korea Coast Guard, AP

by Natalie DiBlasio, USA TODAY

by Natalie DiBlasio, USA TODAY

All crewmembers who helped navigate the now-sunken South Korean ferry are in custody, accused of negligence and failing to help passengers in need in the accident that left more than 300 dead or missing on April 16.

The captain initially told passengers to stay in their rooms and took half an hour to issue an evacuation order. By then, the ship was tilting too severely for many people to get out.

Yang Jung-jin of the joint investigation team said two helmsmen and two members of the steering crew were taken in on preliminary arrest warrants issued late Friday, the Associated Press reported. South Korean television aired video of the police escorting the four men to court. All four wore baseball caps that hid their faces, and at least one was limping. Eleven other crew members, including the captain, had been formally arrested earlier.

Capt. Lee Joon-seok told reporters after his arrest that he withheld the evacuation order because rescuers had yet to arrive and he feared for passengers' safety in the cold water.

Helmsman Oh Yong-seok, one of those arrested Saturday, has said he and several crew members did their best to save people. He said that he and four crew members worked from nearby boats to smash windows on the sinking ferry, dragging six passengers stuck in cabins to safety.

The seven surviving crew members who have not been arrested or detained held non-marine jobs such as chef or steward, Yang said in a telephone interview from Mokpo, the southern city near the wreck site where prosecutors are based. A court hearing was held Saturday to determine whether formal arrest warrants will be issued against the four newly detained crew members.

Also on Saturday, prosecutors accused the vessel traffic service on Jindo of neglecting its duty to monitor the ferry as it sailed nearby, the South Korean Yonhap news agency reported.

Prosecutors said the service was unaware of the emergency situation for about 18 minutes while the ship lost its balance and was drifting.

The Ministry of Oceans and Fisheries plans to make it mandatory for newly built passenger ships or second-hand passenger ships to be fitted with voyage data recorders - the equivalent of black boxes on aircraft, according to the U.N. International Maritime Organization.

Ten days after the sinking, 187 bodies have been recovered and 115 people are believed to be missing, though the government-wide emergency task force has said the ship's passengers list could be inaccurate. Only 174 people survived, including 22 of the 29 crew members.

Divers have reached two large rooms where many victims might be. The rooms are sleeping units designed for many people - one in the stern and one in the bow. Fifty students from Danwon High School in Ansan were booked into one of them.

However, the search was put on hold because of weather.

"This morning (the divers) did a primary dive, but because of the strong current they were losing their masks, so we have stopped the dive for now," Kim Jin-hwang, a South Korean navy official in charge of commanding the dive search, said in a briefing at Jindo.

He said the search would resume once conditions improve, but it was unclear when that would happen.

The high school that lost hundreds of students and teachers in the accident planted a magnolia sapling from President Obama on Saturday in a token of sympathy and condolences, Yonhap reported.

Obama brought the sapling from the White House when he came to Seoul on a two-day official visit that began Friday, with a message of "deep sympathy that the American people have for the families and loved ones of those who perished in this tragedy."